Disk drive with magnetic head for perpendicular magnetic recording

Abstract

A disk drive of a perpendicular magnetic recording system uses a double-layered disk medium including a soft magnetic layer. This disk drive is configured to suppress any adverse effect on a read head element under a magnetic field of a magnetic disturbance applied in a perpendicular direction, which might be caused to occur by being accentuated by a soft magnetic layer.

What is claimed is: 
     
       1. A disk drive comprising:
 a disk medium having a substrate, a magnetic recording layer and a soft magnetic layer interposed between the substrate and the magnetic recording layer; and 
 a magnetic head having a read head element for detecting a magnetic field from the magnetic recording layer and shielding members to shield the read head element, 
 wherein parameters are set for the disk medium and the magnetic head to satisfy a relation
     tg (μ−π4(1−exp(−π t/g )))<2 πd ( d+t ) where
 
 
 t: the thickness of the soft magnetic layer; 
 μ: the permeability of a direction perpendicular to the surface of the soft magnetic layer when an influence of a diamagnetic field is removed; 
 g: a distance from one of the shielding members to another one of the shielding members with the read head element disposed between said one and said another one of the shielding members; and 
 d: a spacing distance from the surface of the soft magnetic layer to a proximal end of the magnetic head. 
 
     
     
       2. The disk drive according to  claim 1 , wherein the magnetic head includes a write head element to allow a perpendicular magnetic recording operation to be performed on the disk medium and further comprising a system for a perpendicular magnetic recording. 
     
     
       3. The disk drive according to  claim 1 , wherein the read head element includes a magnetoresistive element arranged between the shielding members and wherein the magnetic head includes a write head element to allow a perpendicular magnetic recording operation to be performed on the disk medium, the write head element being separate from the read head element. 
     
     
       4. The disk drive according to  claim 1 , wherein the read head element includes a magnetism-detection element including a giant magnetoresistive element.